Sleep quality of offshore wind farm workers in the German exclusive economic zone: a cross-sectional study

OBJECTIVES: To assess the quality of sleep of employees in the German offshore wind industry and to explore factors associated with poor sleep quality. DESIGN: Web-based cross-sectional survey. SETTING: Offshore companies operating in wind farms within the German exclusive economic zone. PARTICIPANTS: Workers with regular offshore commitments and at least 28 days spent offshore in the past year (n=268). OUTCOME MEASURES: Sleep quality in the past 4 weeks, troubles falling asleep or sleeping through in the past 4 weeks, differences in sleep quality between offshore deployments and onshore leaves. RESULTS: Having problems with sleep onset was reported by 9.5% of the respondents. 16.5% reported troubles with maintaining sleep three or more times per week. The overall quality of sleep was rated as very bad by only 1.7% of the participants. 47.9% of the workers reported their quality of sleep to be worse during offshore commitments than when being onshore. Higher levels of exposition to noise, vibrations and poor air quality were associated with sleeping troubles and poorer sleep quality. Sharing the sleep cabin with colleagues was associated with troubles sleeping through. No association was found for working in rotating shifts and for regularity of the offshore commitments. CONCLUSIONS: Workers in our study showed frequent sleep problems and poorer sleep quality offshore than onshore. Our results indicate that higher degrees of exposure to noise, vibrations and artificial ventilation are associated with poor sleep quality rather than organisational factors such as shift-work and type of working schedule. In view of the high demands of the offshore workplace and the workers’ particular recovery needs, addressing sleep disorders should be part of any health and safety management strategy for this workplace.